Sysfs doesn't allow two devices with the same name, but we register a sysfs entry for each cuse device without checking for name collisions. This extends the registration to first check whether the name was already registered.
To avoid race-conditions between the name-check and linking the device, we need to protect the whole registration with a mutex. Signed-off-by: David Herrmann <[email protected]> --- Hi Changes in v2 include: - move mutex-conversion into a separate patch - check every list in the cuse_conntbl array, not only the current one fs/fuse/cuse.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c index e830dab..c56c84c 100644 --- a/fs/fuse/cuse.c +++ b/fs/fuse/cuse.c @@ -308,14 +308,14 @@ static void cuse_gendev_release(struct device *dev) */ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req) { - struct cuse_conn *cc = fc_to_cc(fc); + struct cuse_conn *cc = fc_to_cc(fc), *pos; struct cuse_init_out *arg = req->out.args[0].value; struct page *page = req->pages[0]; struct cuse_devinfo devinfo = { }; struct device *dev; struct cdev *cdev; dev_t devt; - int rc; + int rc, i; if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) { @@ -359,15 +359,24 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req) dev_set_drvdata(dev, cc); dev_set_name(dev, "%s", devinfo.name); + mutex_lock(&cuse_lock); + + /* make sure the device-name is unique */ + for (i = 0; i < CUSE_CONNTBL_LEN; ++i) { + list_for_each_entry(pos, &cuse_conntbl[i], list) + if (!strcmp(dev_name(pos->dev), dev_name(dev))) + goto err_unlock; + } + rc = device_add(dev); if (rc) - goto err_device; + goto err_unlock; /* register cdev */ rc = -ENOMEM; cdev = cdev_alloc(); if (!cdev) - goto err_device; + goto err_unlock; cdev->owner = THIS_MODULE; cdev->ops = &cuse_frontend_fops; @@ -380,7 +389,6 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req) cc->cdev = cdev; /* make the device available */ - mutex_lock(&cuse_lock); list_add(&cc->list, cuse_conntbl_head(devt)); mutex_unlock(&cuse_lock); @@ -394,7 +402,8 @@ out: err_cdev: cdev_del(cdev); -err_device: +err_unlock: + mutex_unlock(&cuse_lock); put_device(dev); err_region: unregister_chrdev_region(devt, 1); -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
